What is Exposure?

Exposure refers to the 'elements at risk' from a natural or man-made hazard event. Elements at risk could include individuals, dwellings or households and communities, buildings and structures, public facilities and infrastructure assets, as well as agricultural commodities and environmental assets. It can also refer to intangible elements such as economic activity and infrastructure networks.

Exposure information can be considered the location and characteristics of the 'elements at risk'. Exposure information is useful for natural hazard risk analysis when those characteristics are related to models of vulnerability that describe how the 'elements at risk' are likely to behave when subjected to natural and artificial forces.

Exposure information development is the practice of locating and characterising the 'elements at risk' within a spatially-enabled data management environment. Location can be expressed as an absolute position for a single element or the extent of a group of elements. Developing nationally consistent exposure information requires access and management of an extensive number of datasets and information where elements and characteristics may be obtained from actual information sources as well as derived or modelled using statistical analysis. Attributes are organised in a consistent way so they can be related to quantitative models of vulnerability. The expression of physical, structural, economic, demographic and social characteristics is particularly important for ensuring compatibility between exposure information and vulnerability models. The development of exposure information is scalable depending on the require complexity of detail (which can vary from hazard to hazard) or the availability and quality of data inputs.

Since exposure information has a spatial dimension, the elements at risk from specific hazards threatening them at various intensities (defined by hazard footprints or a user-defined extent) can be rapidly identified through spatial analysis. When this information is related to models of vulnerability, it is possible to quantify potential impact in terms of the damage to buildings and infrastructure assets, resulting economic loss and expected casualties from one or more modelled hazard events.

Understanding the potential impacts of a hazard event through Exposure Information allows the Australian Government, State jurisdictions and emergency management and planning agencies to make informed, evidence-based decisions to prepare, respond and recover from any events.

This image is a triangle labelled on the bottom edge with Exposure. The left hand side of the triangle is labelled with Hazard and the right hand side with Vulnerability. Risk is the label inside the triangle and along the sides reads Exposure, Hazard and Vulnerability. The Hazard section of the triangle lists earthquake, flood, tsunami, cyclones and landslide. Exposure lists people, buildings, businesses and infrastructure information. Vulnerability lists engineering, economic and social information

This diagram illustrates the concept of risk which combines an understanding of the likelihood of a hazardous event occurring with an assessment of its impact where: Risk = Hazard x Exposure x Vulnerability